Aliphatic-aromatic biodegradable polyesters obtained starting from terephthalic acid and dialcohols are known in the literature and on the market. The presence of the aromatic component in the chain is important to obtain polymers with a high enough melting temperature and a suitable crystallisation rate.
Still the terephthalic acid is of synthetic origin and its potential production from renewable sources is excessively complex. This restricts the chances of significantly reducing the environmental impact of the polyesters of this type currently on the market in terms of the non-renewable-carbon feedstock involved, despite their biodegradability.
Furthermore, although an increase of the terephthalic acid content improves the mechanical and thermal properties of the aliphatic-aromatic polyesters, its high content decreases the percentage of biodegradation of said polyesters. Consequently, were it possible to maintain suitable biodegradation properties and performance in use, the presence of high percentages of aromatic acid of renewable origin in the chain would be desirable. Indeed, this would enable a polymer with high mechanical and thermal properties to be obtained from a feedstock deriving from a renewable source accounting for a very large proportion of the total carbon, that could even be as high as 100% of the total carbon. In fact, the use of monomers of vegetable origin contributes to a reduction of the CO2 in the atmosphere and to a more limited use of non-renewable resources.